Method and Apparatus for Industrial Production of an Extract by Solid-Liquid Extraction

Abstract

The industrial production of an extract by means of solid-liquid extraction improves the exchange of substances during extraction and allows enhanced dehumidification of a raffinate with residual moisture.

The extraction is enhanced during a first dwell time by at least partially flooding a vessel in the form of at least one flow discharged with a secondary solvent or the obtained extract, swirling and keeping in suspension the primary mixture within the vessel by supplying the secondary solvent or the obtained extract via a foot area of the vessel, and/or moving the vessel relative to the extraction container within the obtained extract.

The secondary solvent or the extract circulates in the extraction container by a circulation guide incorporating the extraction container from top to bottom relative to the extraction container, and the extract freed from raffinate with residual moisture obtained by dehumidification is supplied to the separated or to be separated extract.

Claims

1. A method for the industrial production of an extract by solid-liquid extraction by means of an extraction container, wherein a secondary solvent located in the extraction container and a primary mixture consisting of a solid primary solvent and a transition component are brought into contact with each other for a predetermined dwell time to obtain the extract, the primary mixture is enclosed in a liquid-permeable vessel within the extraction container, the primary mixture with a predetermined second mass is introduced into the vessel located in the extraction container, the extraction container is filled with a predetermined first mass of the secondary solvent, the obtained extract and a complementary portion of raffinate are separated from each other after the predetermined dwell time, an extract freed from the raffinate with residual moisture is discharged from the extraction container, and the residual moisture consisting of extract is at least partially removed from the raffinate with residual moisture through dehumidification by mechanical pressing in the vessel and is supplied to the obtained extract, the method comprising: (i) one of: introducing the primary mixture having the predetermined second mass into the vessel located in the extraction container, or placing the vessel filled with the primary mixture having the predetermined second mass into the extraction container; (ii) enhancing the solid-liquid extraction during a first dwell time by at least one of: at least partially flooding the vessel in the form of at least one flow discharged in a planned and targeted manner with the secondary solvent or the obtained extract, swirling and keeping in suspension the primary mixture within the vessel by supplying the secondary solvent or the obtained extract via a foot area of the vessel through an upwardly directed additional flow, or moving the vessel relative to the extraction container within the obtained extract; (iii) circulating the secondary solvent or the obtained extract in the extraction container by a circulation guide incorporating the extraction container from top to bottom relative to the extraction container; (iv) supplying extract ((C∞B)**) obtained by dehumidification and freed from raffinate with residual moisture to the extract freed from raffinate with residual moisture that is already separated or to be separated; and (v) filling the extraction container with a predetermined additional first mass of the secondary solvent after the first dwell time according to step, wherein the solid-liquid extraction is continued with a second dwell time.

2. (canceled)

3. (canceled)

4. The method according to claim 1, wherein the dehumidification starts at the earliest upon the commencement of drying out a first part of the raffinate with residual moisture in the vessel remaining in the extraction container.

5. (canceled)

6. The method according to claim 1, wherein all the extract ((C∞B)**) that is obtained and freed from raffinate with residual moisture is subjected to filtering to separate undesirable particles that pass through the outlets in the vessel.

7. The method according to claim 6, wherein all the extract that is obtained and freed from raffinate with residual moisture is subject to separation in a centrifugal field for pre-clarification and thereby becomes a pre-clarified extract.

8. The method according to claim 1, wherein an automatic or forced discharging of the extract that is obtained and freed from raffinate with residual moisture is additionally supported by a gas pressure from a gaseous propellant that is applied to a free surface of the extract freed from raffinate with residual moisture.

9. The method according to claim 1, wherein the extraction container is designed as a discontinuously working homogeneous reaction container.

10. An apparatus for the industrial production of an extract by solid-liquid extraction by means of an extraction container that inside has at least one liquid-permeable vessel for receiving a primary mixture consisting of a solid primary solvent and a transition component as part of the extraction container, and is configured to bring a secondary solvent into contact with the primary mixture, and to separate the generated results of extraction into a raffinate with residual moisture and into an extract freed from raffinate with residual moisture, wherein the extraction container possesses at least one supply connection for supplying the secondary solvent and a connection for draining the extract freed from raffinate with residual moisture, the connection discharges into a drain line, from the drain line, a circulating line branches off at a first branching point and, viewed in the direction of flow, branches after a conveying apparatus into an additional supply connection leading to an interior of the extraction container, the additional supply connection continues in a top pipe that discharges above the vessel, the top pipe is alternatively or additionally fluidically connected to a flexible pipe, and the flexible pipe runs fluidically to a ring line that is arranged in the foot area of the vessel and extends radially on the inside of the foot area and over its entire circumference and, at its top side facing the interior of the vessel, has a plurality of exit openings arranged distributed over the circumference of the ring line, the extraction container has a moving apparatus that is configured to set the vessel within the extraction container into a back-and-forth first translatory movement, and/or into a first rotary movement (R1) relative to the extraction container, the apparatus possesses a pressing apparatus that is configured to press a content of the vessel, and a control apparatus (38) is provided that is connected in terms of signaling to at least the moving apparatus and the pressing apparatus.

11. The apparatus according to claim 10, wherein the additional supply connections comprises three additional supply connections that continue in associated piping, of which a bottom pipe discharges below, the top pipe discharges above, and a middle pipe discharges in the region of the circumference of the vessel.

12. The apparatus according to claim 11, wherein the middle pipe discharges into a ring line that encloses the vessel and has second outlets, wherein the second outlets face the vessel.

13. (canceled)

14. The apparatus according to claim 10, wherein viewed in the direction of flow, a filter apparatus is arranged after the first branching point in the drain line.

15. The apparatus according to claim 14, wherein viewed in the direction of flow, a centrifugal separator is upstream from the filter apparatus.

16. The apparatus according to claim 10, wherein the extraction container is designed as a discontinuously working homogeneous reaction container.

17. The apparatus according to claim 10, wherein the extraction container has a third supply connection (18) for supplying a compressed gas in the region of its top end.

18. The apparatus according to claim 10, wherein the extraction container has more than one vessel arranged in one of: a single axis or multi-axis rowed arrangement, or a single circular, or concentric multi-circular arrangement in each case with or without occupying the center; and the moving apparatus is configured to supply the more than one vessel with first or secondary mechanical energy.

19. The apparatus according to claim 18, wherein in the rowed arrangement of the more than one vessel, the first translatory movement of an individual vessel is overlapped by a second back-and-forth translatory movement whose direction is determined by the direction of the particular axis that is formed by the axes of symmetry of the single-axis or multi-axis rowed arrangement of the more than one vessel.

20. (canceled)

21. The vessel for the apparatus according to claim 10, wherein the vessel in the form of a liquid-permeable, modified vessel is designed such that it forms an enclosed chamber for storing the primary mixture through which an inner passage runs completely from one to the other face of the liquid-permeable, modified vessel.

22. The vessel according to claim 21, wherein the enclosed chamber has a ring-cylindrical shape, and the inner passage extends from one to the other face of the enclosed chamber.

23. The method according to claim 1, wherein the extract comprises a tea concentrate.

24. The apparatus according to claim 10, wherein the connection is used for supplying the secondary solvent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The invention is represented in more detail by the following description and the appended figures of the drawing and the claims. The invention can be realized in a wide range of embodiments of a method for producing an extract by means of solid-liquid extraction of the generic type. Moreover, the invention is realized in a wide variety of embodiments of a device for producing an extract by solid-liquid extraction and a vessel for this device. In the following, the method, the device and the vessel will be described in a preferred use case for producing a tea extract with reference to the drawing.

[0053] FIG. 1 shows a schematic representation of a device according to the invention with an extraction container according to the invention and a liquid-permeable vessel according to the invention.

[0054] FIG. 2 shows a schematic representation of a cross-section of the extraction container corresponding to a sectional identified in FIG. 1 with line “E-F”, wherein only the cutaway inner region of the extraction container is depicted.

[0055] FIG. 3A shows a schematic diagram of a cross-section of a substantially cylindrical extraction container within a device according to FIG. 1 with four liquid-permeable vessels in a single circular arrangement.

[0056] FIG. 3B shows a schematic diagram of a cross-section of a substantially cuboid extraction container within a device according to FIG. 1 with four liquid-permeable vessels in a single-axis rowed arrangement.

[0057] FIG. 4 shows a schematic representation of a perspective of a liquid-permeable modified vessel in a ring-cylindrical shape with an inner passage.

[0058] FIG. 5 shows a flow chart of the method according to the invention.

DETAILED DESCRIPTION

[0059] General

[0060] Initially a few basic notes are offered in advance to help understand the following symbols for illustrating solid-liquid extraction, or respectively solid-liquid hot extraction (with regard to the following and also preceding notation: 1. terms for the generic case come first; 2. [production of tea concentrate] comes second).

[0061] A solid-liquid extraction exists for example when tea concentrate is extracted from tea leaves with the assistance of water. Extraction is therefore not complete decomposition, because only one of the components to be separated is in an approximately pure state; the others are only relocated and are present in a mixture after the extraction.

[0062] A feed mixture (A∞B) is termed “primary mixture” [tea leaves], and a solution generated by extraction is termed “secondary mixture” or extract (C∞B) [tea concentrate], wherein the notation (A∞B), or respectively (C∞B) designates the phase “mixture”, or respectively “solution”. A substance transitioning from one phase to the other is termed a “transition component” [theine and other desirable or undesirable accompanying substances] that in the following will be identified as B. A non-transitioning component of the primary mixture is a “primary solvent” or a carrier material A [carrier material before extraction]. After extraction, it occurs in a nearly pure state as a “raffinate” A (primary solvent after extraction) [extracted tea leaves], whereas the extract (C∞B) [tea concentrate] is composed of a secondary solvent C [water; hot extraction: hot water or boiling water.fwdarw.reduced hereinafter to hot water] and the transition component B [theine and other desirable or undesirable accompanying substances]. The above solid-liquid extraction or solid-liquid hot extraction can be depicted as follows using the above symbols by the following formula (1) (see also FIGS. 1 and 5):

(A∞B)+C.fwdarw.(C∞B)+A,  (1)

wherein the term (A∞B)+C will hereinafter be termed a mixture (of the primary mixture and secondary solvent) [mixture (of tea leaves and hot water)], and the term (C∞B)+A will hereinafter be termed a mixture (of extract+raffinate after extraction) [tea concentrate+extracted tea leaves].

[0063] Device (FIGS. 1 to 4)

[0064] A device 1 according to the invention for the industrial production of the extract (C∞B) by means of solid-liquid extraction, in particular solid-liquid hot extraction, by means of an extraction container 10, 100 according to the invention is shown in FIG. 1.

[0065] The extraction container 10, 100 incorporates at least one liquid-permeable vessel 12, 12.1 provided with first outlets 13 for receiving the primary mixture (A∞B), consisting of the solid primary solvent A and the transition component B. The vessel 12, 12.1 can form any desired volume; preferably, a cylindrical or prismatic shape whose longitudinal axis is preferably oriented in the direction of the longitudinal axis of the extraction container 10, 100. The extraction container 10, 100 is configured to bring the secondary solvent C into contact with the primary mixture (A∞B), and to separate the generated results of extraction, the extract (C∞B), into a raffinate with residual moisture A.sup.+ and into an extract (C∞B)** freed from raffinate with residual moisture A.sup.+.

[0066] In a top region, a headspace 10.1, the extraction container 10, 100 possesses a first supply connection 14 with a first supply valve 14a for supplying the secondary solvent C that is added with a predetermined first mass M, and where it forms a first free surface N1, a first liquid level. If necessary, a second supply connection 16 is provided in the first headspace 10.1 with a second supply valve 16a through which the vessel 12, 12.1 located in the extraction container 10, 100 is filled with a primary mixture (A∞B) [tea leaves] having a predetermined second mass m. The first mass M and the second mass m together yield a corresponding mixture (A∞B)+C [mixture of tea leaves and hot water]. A foot area 10.2 of the extraction container 10, 100 has a connection 24 with a connection valve 24a for draining the extract (C∞B)** freed from raffinate with residual moisture A.sup.+, and if needed for supplying the secondary solvent C. Moreover, at the top end of the headspace 10.1, a third supply connection 18 with a third supply valve 18a is provided for supplying a gaseous propellant, a compressed gas G, with a gas pressure p. While filling the extraction container 10, 100, a pressure equilibrium is usefully established by draining displaced air L via the third supply connection 18 and the associated third supply valve 18a. The extraction container 10, 100 possesses insulation D for thermal insulation against its environment.

[0067] The connection 24 discharges into a drain line 26 that, viewed in the direction of flow and preferably vertically spaced from the connection 24 by a sufficient supply height in the direction of gravity, has a first shutoff valve 48 after a joining point 46 into which a first supply line section 41 discharges. The drain line 26 furthermore accommodates a second shutoff valve 50, also viewed in the direction of flow, after a first branching point 28. Following the second shutoff valve 50, viewed in the direction of flow, a filter apparatus 36 is arranged in the drain line 26 for separating fine and very fine particles from the extract, wherein by means of the filter apparatus 36, the extract becomes filtered extract (C∞B) from extract (C∞B)** freed from raffinate with residual moisture A.sup.+. The first supply line section 41 can be shut off by a third shutoff valve 52. A supply line 40, through which the secondary solvent C with the first mass M and an additional first mass ΔM is provided, branches at a second branching point 44 into the first supply line section 41 and into a second supply line section 42, wherein the latter is connected via the first supply valve 14a to the first supply connection 14.

[0068] For preliminary clarification of the extract (C∞B)** freed from raffinate with residual moisture, a centrifugal separator 34 for separating coarser particles P that have passed out of the extraction container 10, 100 through the first outlets 13 of the vessel 12, 12.1 while discharging the extract (C∞B)** freed from raffinate with residual moisture, is optionally upstream from the filter apparatus 36, also viewed in the direction of flow. As a result, the extract (C∞B)** freed from raffinate with residual moisture discharged at this point becomes a pre-clarified extract (C∞B)*, which has the effect of extending the service life of filter device 36.

[0069] A circulating line 30 branches from the drain line 26 at the first branching point 28 and, viewed in the direction of flow, branches into at least one additional supply connection 20 along the way through a fourth shutoff valve 54 and a downstream delivery apparatus 32, wherein three additional supply connections 20, 20.1, 20.2 are provided in the exemplary embodiment that each lead to the interior of the extraction container 10, 100. The additional supply connections 20, 20.1, 20.2 can each be shut off with an associated additional shutoff valve 20a, 20.1a, 20.2a.

[0070] In one proposed embodiment, the three additional supply connections 20, 20.1, 20.2 continue in associated piping 21, 22, 23, of which one bottom pipe 21 discharges below, one top pipe 22 discharges above, and one middle pipe 23 discharges in the region of the circumference of the vessel 12, 12.1. The middle pipe 23 leads into a first ring line 23a enclosing the vessel 12, 12.1 (FIGS. 2 and 1), wherein preferably at least two connections are provided that are arranged diametrically opposite to each other, or respectively preferably evenly distributed over the circumference of the first ring line 23a. The first ring line 23a is preferably provided, in the region of its circumferential region facing the vessel 12, 12.1, with a plurality of second outlets 23b preferably distributed evenly over the circumference that enable the vessel 12, 12.1 filled with primary mixture (A∞B) to be flooded with secondary solvent C, or with the generated extract (C∞B)** freed from raffinate with residual moisture in the form of a third flow S3. A planned and targeted first flow S1 is discharged through the bottom pipe 21, and such a second flow S2 is discharged through the top pipe 22 in the form of an above-described flooding of the particular face of the vessel 12, 12.1.

[0071] The top pipe 22 is optionally or also fluidically connected to a pipe 25a that is flexible at least in its connecting region. It either fluidically leads from the outside or inside of the vessel 12, 12.1 to a second ring line 25 arranged in a foot area of the vessel 12; 12.1 that extends radially there on the inside and over its entire circumference. On its top side facing the interior of the vessel 12; 12.1, the second ring line 25 has a plurality of exit openings arranged distributed over its circumference through which a fourth flow S4, which can correspond to the second flow S2 or a part thereof, is discharged into the interior of the vessel 12, 12.1.

[0072] The extraction container 10, 100 has a moving apparatus 60 that is configured to set the vessel 12, 12.1 within the extraction container 10, 100 into a back-and-forth first translatory movement T1, and/or into a first rotary movement R1 by supplying first and second mechanical energy ME1, ME2. The first mechanical energy ME1 is associated with the filling level of the extraction container 12, 12.1 with the first mass M (first free surface N1), and the second mechanical energy ME2 is associated with that of the first mass M and the additional first mass ΔM (a second free surface N2).

[0073] The device 1 possesses a pressing apparatus 70 that, in the exemplary embodiment, is arranged and configured in the extraction container 10, 100 to press a content of the vessel 12, 12.1 therein. A pressure Pr acts for example on a movably designed partial surface of the vessel 12, 12.1, for example in the form of a liquid-permeable plunger, wherein a reaction force to the pressure Pr is generated by supports 72 for the pressing apparatus as shown in FIG. 1.

[0074] If the device 1 is configured to fill the vessel 12, 12.1 outside of the extraction container 10, 100 with primary mixture (A∞B) (a second mode of operation), the pressing apparatus 70 and the associated supports 72 can also be usefully arranged outside of the extraction container 10, 100. In this case, the dehumidification according to the invention of the raffinate with residual moisture A.sup.+ can also usefully be carried out by mechanically pressing same outside of the extraction container 10, 100. Moreover, in the last-mentioned second mode of operation, after placing the vessel 12, 12.1 filled with primary mixture (A∞B), the extraction container 10, 100 is either filled with secondary solvent C as described above, or the related vessel 12, 12.1 is lowered into the secondary solvent C added to the extraction container 10, 100 with the first mass M.

[0075] If, in a first mode of operation, the vessel 12, 12.1 in the extraction container 10, 100 is filled with the primary mixture (A∞B) [tea leaves], the second supply connection 16 is usefully connected to a product-friendly, preferably rotating delivery apparatus 56 that preferably has a screw conveyor 56a that is driven by a drive 56b, preferably by a controllable drive motor MA. The primary mixture (A∞B) is kept in a storage tank 56c from which it runs to the screw conveyor 56a, preferably prepared with water into a sludge. In both modes of operation, the extract (C∞B)** freed from raffinate with residual moisture through dehumidification by means of pressing can be supplied to the extract (C∞B)** freed from raffinate with residual moisture that is already separated or to be separated.

[0076] A control apparatus 38 is provided that is connected in terms of signaling by signal transmission lines 38a to at least the moving apparatus 60 and the pressing apparatus 70 (signal connections a, b, c). The supply valves 14a, 16a, 18a and 20a to 20.2a, the connection valve 24a, the delivery apparatus 32 and the shutoff valves 48, 50, 52 and 54 are controlled in automatic mode by the control apparatus 38 via the signal connections d, e, f, and g1 to g3, h, i, and j, k, l, and n.

[0077] Additional extraction containers 10, 100 of the above-described type can be connected to the drain line 26 between the first branching point 28 and the second shutoff valve 50 to increase the production output of the device 1.

[0078] The extraction container 10 in a substantially cylindrical shape is configured to accommodate inside itself more than one vessel 12, 12.1 in a single circular FIG. 3A or concentric multi-circular arrangement (not shown) in each case with or without occupying the center. The rotary movement R1 can be overlapped in each case by the first translatory movement T1.

[0079] A modified extraction container 100 in a substantially cuboid embodiment FIG. 3B is configured to accommodate in itself more than one vessel 12, 12.1 in a single axis or multi-axis rowed arrangement. In this arrangement of the vessels 12, 12.1, the first translatory movement T1 of the individual vessel 12, 12.1 overlaps a second back-and-forth translatory movement T2 whose direction r is determined by the direction of the particular axis that is formed by the axes of symmetry S of the single-axis or multi-axis rowed arrangement. The translatory movements T1, T2 can be overlapped in each case by the first rotary movement R1.

[0080] FIG. 4 shows a liquid-permeable, modified vessel 12.1 that forms an enclosed chamber 12.1b for storing the primary mixture (A∞B) through which an inner passage 12.1a runs completely from one to the other face of the modified vessel 12.1. The chamber 12.1b preferably has a ring-cylindrical shape with a preferably cylindrically designed inner passage 12.1a that extends completely from one to the other face of the chamber 12.1a. An outer diameter of the modified vessel 12.1 is identified with D1, its inner diameter (inner passage 12.1a) is identified with inner diameter D2, and its height is identified with H. For the predetermined second mass m of primary mixture (A∞B) in the modified vessel 12.1, the required penetration depth to be overcome by the secondary solvent C or the existing extract to the core of the particular bulk becomes all the more smaller the smaller the difference in diameter D1-D2, and therefore the greater the height H (slim ring cylinder). The first translatory movement T1 and the first rotary movement R1 are usefully oriented along the preferably vertically aligned axis of symmetry S of the ring-cylindrical, modified vessel 12.1.

[0081] Method (FIGS. 1 and 5)

[0082] A method according to the invention is characterized by the method steps (i) to (v) described above, whose interrelationship and meaning are graphically illustrated in a flowchart in FIG. 5. The following description of the method offers the terminology for production of tea concentrate as indicated in the list of reference numerals for the employed abbreviations in the concordance of superordinate terms, in addition to the superordinate terms. The new method steps, or respectively treatment features in comparison to the prior art, are highlighted in FIG. 5 by a thicker line.

[0083] According to step (i), a primary mixture (A∞B) [tea leaves] with the predetermined second mass m is introduced into the vessel 12, 12.1 located in the extraction container 10, 100 via the second supply connection 16, or the vessel 12, 12.1 filled with primary mixture (A∞B) with a predetermined second mass is placed to the extraction container 10, 100 (arrow at (i))—(FIG. 5: Specification of (A∞B) and m, .fwdarw.m((A∞B)); FIG. 1).

[0084] In a manner known per se, the extraction container 10, 100 is filled with a predetermined first mass M of the secondary solvent C [hot water] corresponding to a predetermined first concentration k1=m/M via the first supply connection 14, or alternatively via the connection 24 up to the first free surface N1 (first liquid level) over a first filling time Δt1 (FIG. 5: Specification of C, M, k1 and Δt1.fwdarw.M(C); FIG. 1).

[0085] The first concentration k1 is defined by equation (1):

[00001]$\begin{array}{cc}k1=\frac{m}{M}=\frac{m\left(A\infty B\right)}{M\left(C\right)}& \left(1\right)\end{array}$

[0086] The subsequent extraction over the first dwell time τ1 [brewing time] can be represented by the following formula (2):

(A∞B)+C.fwdarw.(C∞B)+A  (2)

[0087] The first mass M of secondary solvent C [hot water] and the second mass m of primary mixture (A∞B) [tea leaves] form, at the beginning of the first dwell time τ1, the mixture (A∞B)+C.

[0088] According to step (ii), solid-liquid extraction intensifies during the first dwell time τ1 through at least one of: at least partially flooding the vessel 12, 12.1 in the form of at least one flow discharged in a planned and targeted manner with the secondary solvent C or the obtained extract (C∞B); swirling and keeping in suspension the primary mixture (A∞B) within the vessel 12, 12.1 by supplying the secondary solvent C or the obtained extract (C∞B) via a foot area of the vessel 12, 12.1 through an upwardly directed fourth flow S4; or moving the vessel 12, 12.1 relative to the extraction container 10, 100 within the obtained extract (C∞B) by supplying first mechanical energy ME1 via the moving apparatus 60.

[0089] According to step (iii), further intensification of the exchange of substances occurs by circulating the secondary solvent C [hot water] or the extract (C∞B) in the extraction container 10, 100 from top to bottom relative to the extraction container 10, 100 by a circulation guide 30 incorporating the extraction container 10, 100.

[0090] After the first dwell time τ1, the mixture (C∞B)+A [tea concentrate+extracted tea leaves] with the overall mass M+m exists, consisting of the extract (C∞B) [tea concentrate] and the raffinate A [tea leaves] (FIG. 5: Specification of ME1 and τ1.fwdarw.(M+m)[(C∞B)+A]; FIG. 1).

[0091] According to step (iv), the extract (C∞B)** freed from raffinate with residual moisture through dehumidification is supplied to the extract (C∞B) freed from raffinate with residual moisture that is already separated or to be separated.

[0092] According to step (v) of the method, the intensity of substance exchange in extraction according to the invention is further improved in that, after the first dwell time τ1 [first brewing time] according to steps (ii, iii), a filling of the extraction container 10, 100 with a predetermined additional first mass ΔM of the secondary solvent C [hot water] is provided.

[0093] The additional first mass ΔM is supplied, corresponding to a predetermined second concentration k2=m/(M+ΔM), via the first supply connection 14, or alternatively via the connection 24 up to the second free surface N2 (second liquid level) over a second filling time Δt2.

[0094] The second concentration k2 is defined by equation (3):

[00002]$\begin{array}{cc}k2=\frac{m}{M+\Delta M}=\frac{m\left(A\infty B\right)}{M\left(C\right)+\Delta M\left(C\right)}=\frac{m\left(A\infty B\right)}{\left(M+\Delta M\right)\left(C\right))}& \left(3\right)\end{array}$

[0095] By this measure, “replenishing with secondary solvent” C [hot water], the concentration gradient that significantly influences the exchange of substances between the substance-exchanging components is increased. According to this measure, it is furthermore provided that the solid-liquid extraction is continued by a second dwell time τ2 [second brewing time]. During the second dwell time τ2, solid-liquid extraction is intensified by at least partially flooding the vessel 12, 12.1 and/or by swirling and keeping in suspension the primary mixture (A∞B) within the vessel 12, 12.1 according to step (ii) with the obtained extract (C∞B), and/or by moving the vessel 12, 12.1 relative to the extraction container 10, 100 within the obtained extract (C∞B) according to step (ii) by supplying secondary mechanical energy ME2 via the moving apparatus 60 (FIG. 5: Specification of Δt, k2, ME2 and τ2.fwdarw.(M+ΔM+m)[(C∞B)+A]; FIG. 1).

[0096] The above-described circulation guide according to step (iii) can advantageously carried out in any phase of the first and second dwell time τ1, τ2.

[0097] In a manner known per se, an extract (C∞B)** [tea concentrate freed from extracted tea leaves with residual moisture] freed from the raffinate with residual moisture is discharged from the extraction container 10, 100 via the connection 24 into the drain line 26.

[0098] A first mass M′ of extract (C∞B)** [tea concentrate freed from extracted tea leaves with residual moisture] freed from raffinate with residual moisture, and a second mass m′ of raffinate with residual moisture A.sup.+ [extracted tea leaves with residual moisture] exist (FIGS. 5, 1).

[0099] In a manner known per se, the raffinate with residual moisture A.sup.+ [extracted tea leaves with residual moisture] is dehumidified by mechanically pressing the raffinate with residual moisture A.sup.+ in the vessel 12, 12.1 by means of the pressing apparatus 70 by applying a pressure Pr over a pressing time Δt3. The extract (C∞B)** freed from raffinate with residual moisture additionally obtained thereby is supplied to the already obtained extract (C∞B)** freed from raffinate with residual moisture A+ (FIG. 5: Specification of Pr and Δt3; FIG. 1).

[0100] As proposed, dehumidification preferably starts at the earliest upon the commencement of drying out a first part of the raffinate with residual moisture A.sup.+ in the vessel 12, 12.1 remaining in the extraction container 10, 100.

[0101] The tea concentrate (C∞B)** freed from extracted tea leaves with residual moisture A.sup.+ is usefully pre-clarified in the centrifugal separator 34 by separating particles P below the separating limit of the first outlets 13 in the vessel 12, 12.1, and then supplied as a pre-clarified tea concentrate (C∞B)* to the filter apparatus 36 that it then leaves as a filtered tea concentrate (C∞B) in order, for example, to be further treated to become a tea beverage.

[0102] The following is a list of reference numbers used in the drawings and this description, with reference to the figures in which they first appear.

TABLE-US-00001 FIGS. 1 to 4 1 Device 10 Extraction container 100 Modified extraction container 10.1 Headspace 10.2 Foot area 12 Vessel (liquid-permeable) 12.1 Modified vessel 12.1a Inner passage 12.1b Chamber 13 First outlets 14 First supply connection 14a First supply valve 16 Second supply connection 16a Second supply valve 18 Third supply connection 18a Third supply valve 20, 20.1, 20.2 Additional supply connections 20a, 20.1a, 20.2a Additional supply valves 21 Bottom pipe 22 Top pipe 23 Middle pipe (first ring line) 23a First ring line 23b Second outlet 24 Connection 24a Connection valve 25 Second ring line 25a Flexible pipe 26 Drain line 28 First branching point 30 Circulation line 32 Delivery apparatus 34 Centrifugal separator 36 Filter apparatus 38 Control apparatus 38a Signal transmission line 40 Supply line 41 First supply line section 42 Second supply line section 44 Second branching point 46 Joining point 48 First shutoff valve 50 Second shutoff valve 52 Third shutoff valve 54 Fourth shutoff valve 56 Delivery apparatus 56a Screw conveyor 56b Drive motor 56c Storage tank 60 Moving apparatus 70 Pressing apparatus 72 Supports (for the pressing apparatus) D Insulation D1 Outer diameter D2 Inner diameter G Gaseous propellant/compressed gas - (air; nitrogen, inert gas) H Height L Air M.sub.A Drive motor (general) ME1 First mechanical energy ME2 Second mechanical energy N1 First free surface (first liquid level) N2 Second free surface (second liquid level) P Particles Pr Pressure R1 First rotary movement S Axis of symmetry S1 First flow S2 Second flow S3 Third flow S4 Fourth flow T1 First translatory movement T2 Second translatory movement a to l, n Signal connection p Gas pressure r Direction

TABLE-US-00002 FIG. 5 Special application: Superordinate terms Production of tea concentrate A Primary solvent Carrier material (before extraction) (before extraction) A Raffinate (=primary solvent after Extracted tea leaves extraction) A.sup.+ Raffinate with residual moisture Extracted tea leaves with residual moisture B Transition component Theine and other desirable and undesirable accompanying substances C Secondary solvent Hot water or boiling Water (A∞B) Primary mixture Tea leaves (tea raw material) (A∞B) + C Mixture of primary mixture and Mixture of tea leaves and hot water secondary solvent (C∞B) Extract Tea concentrate (filtered in the end step) (C∞B)** Extract freed from raffinate with Tea concentrate freed from extracted residual moisture tea leaves with residual moisture (C∞B)* Pre-clarified extract Pre-clarified tea concentrate (C∞B) + A Mixture (extract + raffinate after Tea concentrate + extracted extraction) tea leaves M first mass (C) first mass (hot water) M' First mass of extract freed from First mass of tea concentrate freed raffinate with residual moisture from extracted tea leaves with residual moisture ΔM additional first mass (C) additional first mass (hot water) k1 First concentration (second mass First concentration (second mass m m of the primary mixture relative of the tea leaves relative to the hot to the secondary solvent water with the first mass M) with the first mass M) .fwdarw.k1 = m/M k2 Second concentration (second Second concentration (second mass mass m of the primary mixture m of the tea leaves relative to relative to the secondary solvent the hot water with the first mass with the first mass M and M and the additional first mass the additional first mass ΔM) ΔM) k2 = m/(M + ΔM) M Second mass ((A∞B)) second mass (tea leaves) m' Second mass of raffinate with Second mass of extracted tea leaves residual moisture with residual moisture Δt1 First filling time (secondary First filling time (hot water with first solvent with first mass M) mass M) Δt2 Second filling time (secondary Second filling time (hot water with solvent with additional first additional first mass ΔM) mass ΔM) Δt3 Pressing time (raffinate with Pressing time (extracted tea leaves residual moisture) with residual moisture) τ1 First dwell time First brewing time τ2 Second dwell time Second brewing time